Time Dividing Analysis of Intermittent Fuel Spray Flows Measured by PDA

Abstract

The article presents the analyzing methods for intermittent and cyclic Diesel type- and gasoline type-sprays. The Diesel type sprays were initiated from a single-hole, a four-holes and a conical spray nozzles, and the gasoline type spray was initiated from an air-assisted spray injector. The measurements have been carried out by using phase Doppler anemometer (PDA). A frequency discriminating center part selection method and a temporal dividing method have been proposed for evaluating the intermittent cyclic spray. Using the frequency discrimination method, it was easy to discuss the intermittent spray characteristics with the mean velocity and the velocity fluctuation, and it was also easy to compare the results between those of continuous sprays and/or gas jets. The temporal dividing method was able to explain unusual correlations between droplet size and velocity of the intermittent sprays from both the conical nozzle and the air assisted injector. An accumulation of large particle was observed by using this method in the conical spray.